A barbeque rosemary plant I bought last year was doing fairly well until a week ago when I noticed some of the leaves were discolored. Then today I saw that the plant was really looking poorly.

I live in California near San Francisco and we have had a lot of rain this spring. Could that have caused the problem? The plant is in a container with potting soil that drains fast and doesn't keep very much water.

An oregano plant next to the rosemary also has a patch of leaves that are not doing well. But at least part of that oregano is growing well. That makes me worry about the rosemary.

UPDATE 1: I see from another person's question that it may be spider mites: Best way to combat Rosemary Mites?

UPDATE 2: I thought the problem might be insects so I used a detergent spray on the plants. That spray brought out in view a bunch of fine webs I had not seen before. They look like spider webs rather than spider mite webs -- too big.

UPDATE 3: I found this link to a site about rosemary pests. My problem seems to be something else. The discoloration on the oregano and the rosemary seems similar. But the problem started long ago on the oregano and just recently on the rosemary.

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1 Answer 1


These look like spider mites. The webs they make can be quite big, and regular spiders can live there as well. Mites like oregano too. Look for them on leaf undersides.

When choosing pesticide, bear in mind that mites are not insects (biologically) so different substances are used to control them (acaricides not insecticides).

White oil spray worked well for mites on rosemary for me (http://www.brunnings.com.au/white-oil.html)

Another option: it could be thrips. (https://en.wikipedia.org/wiki/Thrips) They make similar discoloration as mites, but they are insects, not spiders.

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